iou computation

[kindeQi]

I have found in the train.py the iou function start_i, end_i = interval[0], interval[1]

intersection = max(0, min(end, end_i) - max(start, start_i)) union = min(max(end, end_i) - min(start, start_i), end - start + end_i - start_i) overlap = float(intersection) / (union + 1e-8)

when the start time is negative, whether the iou should be 0 anyway?